Process for producing polymer having crosslinkable silyl group and curable composition

ABSTRACT

A process for producing a crosslinkable silyl group-containing polymer which is excellent in oil resistance, heat resistance, weatherability, low staining properties, and compression set characteristics, includes the steps of radically polymerizing a vinyl monomer in the presence of a thiocarbonylthio group-containing compound with a specific structure, and introducing crosslinkable silyl groups. Also provided is a curable composition which contains the polymer and which is easy to handle.

RELATED APPLICATIONS

This is a 371 application of PCT/JP02/04669 filed on 14 May 2002,claiming priority to Japanese Application No. 2001-165026 filed on 31May 2001, the entire contents of which are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to a process for producing a crosslinkablesilyl group-containing polymer and a curable composition. Moreparticularly, the invention relates to a process for producing acrosslinkable silyl group-terminated vinyl polymer and a curablecomposition containing the polymer.

BACKGROUND ART

Crosslinkable silyl group-terminated polymers are used as curablecompositions for sealants, adhesives, pressure-sensitive adhesives,paint, and potting materials. As the crosslinkable silylgroup-terminated polymers, polysiloxane, polyoxypropylene, andpolyisobutylene polymers have been known. However, the curablecompositions using such polymers have many problems. For example,although polysiloxane polymers exhibit excellent weatherability, heatresistance, and cold temperature resistance, they exhibit unsatisfactoryoil resistance, low staining properties, paintability, and gas-barrierproperties. Although polyoxypropylene polymers exhibit low stainingproperties and satisfactory paintability, they have insufficientweatherability. With respect to polyisobutylene polymers, althoughexcellent weatherability, low water vapor transmission, and gas-barrierproperties are exhibited, they are difficult to handle due to their highviscosity, and it takes a long time to perform moisture-curing (curingby water).

As moisture-curing compositions which are excellent in heat resistance,weatherability, oil resistance, and low staining properties, and whichare easy to handle, curable compositions containing crosslinkable silylgroup-terminated acrylic polymers as principal components have beensuggested.

Examples of methods for producing acrylic polymers contained in thecompositions include methods disclosed in Japanese Examined PatentApplication Publication Nos. 3-14068 and 5-72427 in which acrylicmonomers are radically polymerized using a crosslinkable silylgroup-containing mercaptan chain transfer agent, a crosslinkable silylgroup-containing disulfide chain transfer agent, or a crosslinkablesilyl group-containing azo polymerization initiator. However, in theseproduction methods, it is difficult to introduce crosslinkable silylgroups into the ends of the polymers reliably, and it is not possible toproduce compositions having satisfactory physical properties. Sincecrosslinkable silyl groups are hydrolyzed, it is not possible to performwater-based polymerization, such as emulsion polymerization orsuspension polymerization. Even when solution polymerization isperformed, since the water content must be controlled strictly, theproduction process becomes complicated.

Japanese Examined Patent Application Publication No. 4-55444 discloses amethod in which a crosslinkable silyl group-containing hydrosilane orcrosslinkable silyl group-containing tetrahalosilane is used as a chaintransfer agent. However, in this method, it is also difficult tointroduce crosslinkable silyl groups into the ends of the polymer athigh yield, and it is not possible to produce cured compositions havingsatisfactory physical properties. Furthermore, as in the above-mentionedexample, since crosslinkable silyl groups are hydrolyzed, it is notpossible to perform water-based polymerization, such as emulsionpolymerization or suspension polymerization. Even when solutionpolymerization is performed, since the water content must be controlledstrictly, the production process becomes complicated.

Japanese Unexamined Patent Application Publication No. 6-211922discloses a method in which a hydroxyl-terminated acrylic polymer isproduced using a hydroxyl-containing polysulfide chain transfer agent inlarge excess relative to an initiator, and then the hydroxyl groups areconverted into crosslinkable silyl groups. However, in this method, alarge amount of chain transfer agent must be used, thus beinguneconomical.

In order to overcome these problems, a process is disclosed in JapaneseUnexamined Patent Application Publication No. 11-80571 in which acrosslinkable silyl group-terminated vinyl polymer is produced by anatom transfer radical polymerization (ATRP) method using a metal complexas a catalyst. However, in the atom transfer radical polymerizationmethod, since the metal complex is used as the catalyst, purificationmust be performed after polymerization and the process becomescomplicated, resulting in a decrease in productivity. In this method, itis also impossible to employ a water-based polymerization technique,such as emulsion polymerization or suspension polymerization.

On the other hand, reversible addition-fragmentation chain transfer(RAFT) polymerization methods are excellent in producing vinylcopolymers because the molecular weight and the molecular weightdistribution are controlled and a wide variety of monomers and a widevariety of polymerization techniques including water-basedpolymerization can be used. The details thereof including the reactionmechanism are described in PCT Publication No. WO98/01478; PCTPublication No. WO99/05099; PCT Publication No. WO99/31144;Macromolecules, 1998, 31, page 5559; Macromolecules, 1999, 32, page2071; Macromolecules, 1999, 32, page 6977; Macromolecules, 2000, 33,page 243; etc. However, these documents do not describe a method forintroducing crosslinkable silyl groups or do not mention a curablecomposition. The present invention relates to a process for introducingcrosslinkable silyl groups into molecular ends by a RAFT polymerizationtechnique, and a curable composition containing, as an essentialcomponent, a crosslinkable silyl group-containing polymer produced bythe RAFT polymerization technique.

DISCLOSURE OF INVENTION

The present invention has been achieved in order to solve the problemsassociated with the conventional methods described above. It is anobject of the present invention to provide a process for producing acrosslinkable silyl group-containing polymer which is excellent in oilresistance, heat resistance, weatherability, low staining properties,and compression set characteristics, in which a water-basedpolymerization technique can also be employed and which requires hardlyany purification. It is another object of the present invention toprovide an easy-to-handle curable composition containing a crosslinkablesilyl group-containing polymer produced by the above process.

The present inventors have conducted intensive research to overcome theproblems described above and have achieved the present invention. Thepresent invention includes a process for producing crosslinkable silylgroup-containing polymers and curable compositions containing thepolymers, which will be described below.

In the process of the present invention, first, a radicallypolymerizable vinyl monomer is radically polymerized by a RAFTpolymerization technique using a thiocarbonylthio group-containingcompound with a specific structure as a chain transfer agent to preparea thiocarbonylthio group-containing polymer. Next, the thiocarbonylthiogroup of the resultant polymer is converted into a mercapto group, andthe polymer and a compound having a crosslinkable silyl group and anisocyanato group in each molecule are coupled via the mercapto group. Acrosslinkable silyl group-containing polymer is thereby produced.

The thiocarbonylthio group-containing compound used in the presentinvention is at least one compound selected from the group consisting ofa compound represented by general formula (1):

(wherein R¹ is a p-valent organic group of 1 or more carbon atoms whichmay contain one of nitrogen, oxygen, sulfur, halogen, silicon,phosphorus, and metal atoms, or which may be a polymer; Z¹ is a hydrogenatom, halogen atom, or monovalent organic group of 1 or more carbonatoms which may contain one of nitrogen, oxygen, sulfur, halogen,silicon, and phosphorus atoms, or which may be a polymer; when pluralZ¹s are present, the plural Z¹s may be the same or different; and p isan integer of 1 or more), and a compound represented by general formula(2):

(wherein R² is a monovalent organic group of 1 or more carbon atomswhich may contain one of nitrogen, oxygen, sulfur, halogen, silicon,phosphorus, and metal atoms, or which may be a polymer; Z² is an oxygenatom (when q=2), sulfur atom (when q=2), nitrogen atom (when q=3), orq-valent organic group of 1 or more carbon atoms which may contain oneof nitrogen, oxygen, sulfur, halogen, silicon, and phosphorus atoms, orwhich may be a polymer; plural R²s may be the same or different; and qis an integer of 2 or more).

In the structure of the thiocarbonylthio group-containing compoundrepresented by general formula (1), R¹ is not particularly limited. Inview of availability of the compound, preferably, R¹ has 1 to 20 carbonatoms, and p is 6 or less. Examples of R¹ include alkyl, substitutedalkyl, aralkyl, substituted aralkyl, a polyvalent aliphatic hydrocarbongroup, a polyvalent aromatic hydrocarbon group, a polyvalent aliphatichydrocarbon group with an aromatic ring, a polyvalent aromatichydrocarbon group with an aliphatic group, a polyvalent aliphatichydrocarbon group containing a heteroatom, and a polyvalent aromaticsubstituted hydrocarbon group containing a heteroatom. In view ofpolymerization activity and availability of the compound, R¹ ispreferably benzyl, 1-phenylethyl, 2-(2-phenyl)propyl, 1-acetoxyethyl,1-(4-methoxyphenyl)ethyl, ethoxycarbonylmethyl,2-(2-ethoxycarbonyl)propyl, 2-(2-cyano)propyl, tert-butyl,1,1,3,3-tetramethylbutyl, 2-[2-(p-chlorophenyl)]]propyl, vinylbenzyl,tert-butylthio, 2-carboxylethyl, carboxylmethyl, cyanomethyl,1-cyanoethyl, 2-(2-cyano)butyl, or any one of organic groups representedby general formulae below, (wherein r is an integer of 0 or more, and sis an integer of 1 or more).

In the above formulae, each of r and s is preferably 500 or less in viewof availability of the compound.

Furthermore, as described above, R¹ may be a polymer. Examples thereofinclude a hydrocarbon group having a poly(ethylene oxide) structure, ahydrocarbon group having a poly(propylene oxide) structure, ahydrocarbon group having a poly(tetramethylene oxide) structure, ahydrocarbon group having a poly(ethylene terephthalate) structure, ahydrocarbon group having a poly(butylene terephthalate) structure, ahydrocarbon group having a polydimethylsiloxane structure, a hydrocarbongroup having a polycarbonate structure, a hydrocarbon group having apolyethylene structure, a hydrocarbon group having a polypropylenestructure, and a hydrocarbon group having a polyacrylonitrile structure.These hydrocarbon groups may contain at least one of oxygen, nitrogen,and sulfur atoms, and may contain a cyano group, an alkoxy group, or thelike. The molecular weight thereof is usually 500 or more. Hereinafter,in the present invention, when a group is a polymer, examples of thepolymer correspond to those described above.

Z¹ in general formula (1) is not particularly limited. When Z¹ is anorganic group, preferably, the organic: group has 1 to 20 carbon atomsin view of availability of the compound. Examples of Z¹ include alkyl,substituted alkyl, alkoxy, aryloxy, aryl, substituted aryl, aralkyl,substituted aralkyl, N-aryl-N-alkylamino, N,N-diarylamino,N,N-dialkylamino, thioalkyl, and dialkylphosphinyl. In view ofpolymerization activity and availability of the compound, Z¹ ispreferably phenyl, methyl, ethyl, benzyl, 4-chlorophenyl, 1-naphthyl,2-naphthyl, diethoxyphosphinyl, n-butyl, tert-butyl, methoxy, ethoxy,methylthio, phenoxy, phenylthio, N,N-dimethylamino, N,N-diethylamino,N-phenyl-N-methylamino, N-phenyl-N-ethylamino, benzylthio,pentafluorophenoxy, or any one of organic groups represented by formulaebelow.

In the structure of the thiocarbonylthio group-containing compoundrepresented by general formula (2), R² is not particularly limited. Inview of availability of the compound, preferably, R² has 1 to 20 carbonatoms. Examples of R² include alkyl, substituted alkyl, aralkyl, andsubstituted aralkyl. In view of polymerization activity and availabilityof the compound, R² is preferably benzyl, 1-phenylethyl,2-(2-phenyl)propyl, 1-acetoxyethyl, 1-(4-methoxyphenyl)ethyl,ethoxycarbonylmethyl, 2-(2-ethoxycarbonyl)propyl, 2-(2-cyano)propyl,tert-butyl, 1,1,3,3-tetramethylbutyl, 2-[2-(p-chlorophenyl)]propyl,vinylbenzyl, tert-butylthio, 2-carboxylethyl, carboxylmethyl,cyanomethyl, 1 -cyanoethyl, 2-(2-cyano)butyl, or any one of organicgroups represented by general formulae below, (wherein r is an integerof 0 or more, and s is an integer of 1 or more).

In the above formulae, each of r and s is preferably 500 or less in viewof availability of the compound.

Although Z² in general formula (2) is not particularly limited, q ispreferably 6 or less. In view of availability of the compound, when Z²is an organic group, preferably, the organic group has 1 to 20 carbonatoms. Examples of Z² include a polyvalent aliphatic hydrocarbon group,a polyvalent aromatic hydrocarbon group, a polyvalent aliphatichydrocarbon group with an aromatic ring, a polyvalent aromatichydrocarbon group with an aliphatic group, a polyvalent aliphatichydrocarbon group containing a heteroatom, and a polyvalent aromaticsubstituted hydrocarbon group containing a heteroatom. In view ofpolymerization activity and availability of the compound, Z² ispreferably any one of the organic groups represented by formulae below,(wherein r is an integer of 0 or more, and s is an integer of 1 ormore).

In the above formulae, each of r and s is preferably 500 or less in viewof availability of the compound.

Specific examples of thiocarbonylthio group-containing compounds used inthe present invention include, but are not limited to, compoundsrepresented by formulae below, wherein Me, Et, Ph, and Ac representmethyl, ethyl, phenyl, and acetyl, respectively; r is an integer of 0 ormore; and s is an integer of 1 or more).

In the above formulae, each of r and s is preferably 500 or less in viewof availability of the compound.

Among the thiocarbonylthio group-containing compounds described above,thiocarbonylthio group-containing compounds in which p is 2 or more arepreferable because it is possible to produce multifunctionalcrosslinkable silyl group-containing polymers. Furthermore, as thethiocarbonylthio group-containing compound used in the presentinvention, a compound represented by general formula (3):

(wherein R³ is a divalent organic group which may contain one ofnitrogen, oxygen, sulfur, halogen, silicon, phosphorus, and metal atoms,or which may be a polymer; each Z³ is a hydrogen atom, halogen atom, ormonovalent organic group of 1 or more carbon atoms which may contain oneof nitrogen, oxygen, sulfur, halogen, silicon, and phosphorus atoms, orwhich may be a polymer; and Z³s may be the same or different), is morepreferable because it is possible to produce a telechelic (i.e.,functional at both ends) crosslinkable silyl group-containing polymer,which exhibits satisfactory physical properties when used as a curablecomposition.

In the structure of the compound represented by general formula (3)which has thiocarbonylthio groups at both ends, R³ is not particularlylimited. In view of availability of the compound, preferably, R³ has 1to 20 carbon atoms. In view of polymerization activity and availability,R³ is preferably any one of organic groups represented by formulaebelow.

Z³ in general formula (3) is not particularly limited, and is the sameas Z¹ in general formula (1).

Specific examples of the thiocarbonylthio group-containing compoundrepresented by general formula (3), which is preferably used in thepresent invention, and which is capable of producing a telechelic (i.e.,functional at both ends) crosslinkable silyl group-containing polymer,include, but are not limited to, compounds represented by formulaebelow, (wherein Me represents methyl and Ph represents phenyl).

The thiocarbonylthio group-containing compounds used in the presentinvention may be used alone or in combination.

The vinyl monomer used in the present invention is not particularlylimited as long as it is radically polymerizable. Examples of vinylmonomers which may be used include methacrylate esters, such as methylmethacrylate, ethyl methacrylate, n-butyl methacrylate, isobutylmethacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate,tridecyl methacrylate, stearyl methacrylate, cyclohexyl methacrylate,benzyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylmethacrylate, dimethylaminoethyl methacrylate, diethylaminoethylmethacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate,ethylene glycol dimethacrylate, triethylene glycol dimethacrylate,tetraethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate,trimethylolpropane trimethacrylate, isopropyl methacrylate, pentylmethacrylate, hexyl methacrylate, heptyl methacrylate, octylmethacrylate, nonyl methacrylate, decyl methacrylate, dodecylmethacrylate, phenyl methacrylate, tolyl methacrylate, isobornylmethacrylate, 2-methoxyethyl methacrylate, 3-methoxybutyl methacrylate,2-aminoethyl methacrylate, 2-methacryloyloxypropyltrimethoxysilane,2-methacryloyloxypropyldimethoxymethylsilane, trifluoromethylmethacrylate, pentafluoroethyl methacrylate, and 2,2,2-trifluoroethylmethacrylate; acrylate esters, such as methyl acrylate, ethyl acrylate,n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, hexyl acrylate,2-ethylhexyl acrylate, cyclohexyl acrylate, octyl acrylate, decylacrylate, dodecyl acrylate, phenyl acrylate, tolyl acrylate, benzylacrylate, isobornyl acrylate, 2-methoxyethyl acrylate, 3-methoxybutylacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, stearylacrylate, glycidyl acrylate, 2-acryloyloxypropyldimethoxymethylsilane,2-acryloyloxypropyltrimethoxysilane, trifluoromethyl acrylate,pentafluoroethyl acrylate, 2,2,2-trifluoroethyl acrylate,3-dimethylaminoethyl acrylate, isobutyl acrylate, 4-hydroxybutylacrylate, tert-butyl acrylate, acrylate of alkyl-modifieddipentaerythritol, ethylene oxide-modified bisphenol A diacrylate,Carbitol acrylate, acrylate of ε-caprolactone-modifieddipentaerythritol, caprolactone-modified tetrahydrofurfuryl acrylate,diacrylate of caprolactone-modified neopentyl glycol hydroxypivalate,ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate,dipentaerythritol pentaacrylate, tetraethylene glycol acrylate,tetrahydrofurfuryl acrylate, tripropylene glycol acrylate,trimethylolpropane ethoxy triacrylate, trimethylolpropane triacrylate,neopentyl glycol diacrylate, diacrylate of neopentyl glycolhydroxypivalate, 1,9-nonandiol acrylate, 1,4-butanediol acrylate,2-propanoic acid[2-[1,1-dimethyl-2-[(1-oxo-2-propenyl)oxy]ethyl]-5-ethyl-1,3-dioxane-5-yl]methylester, 1,6-hexanediol acrylate, pentaerythritol triacrylate,2-acryloyloxypropylhydrogen phthalate, methyl 3-methoxyacrylate, andallyl acrylate; aromatic alkenyl compounds, such as styrene,α-methylstyrene, p-methylstyrene, p-methoxystyrene, divinylbenzene, andvinylnaphthalene; vinyl cyanide compounds, such as acrylonitrile andmethacrylonitrile; conjugated diene compounds, such as butadiene andisoprene; halogen-containing unsaturated compounds, such as vinylchloride, vinylidene chloride, tetrafluoroethylene, hexafluoropropylene,vinylidene fluoride, vinyl bromide, and chloroprene; silicon-containingunsaturated compounds, such as vinyltrimethoxysilane,vinyltriethoxysilane, vinyltrimethylsilane, vinyltriphenylsilane, andvinyltriethylsilane; unsaturated dicarboxylic compounds, such as maleicanhydride, maleic acid, maleate monoesters, maleate diesters, fumaricacid, fumarate monoesters, and fumarate diesters; vinyl ester compounds,such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate,vinyl cinnamate, divinyl carbonate, vinylethyl carbonate, andvinylphenyl carbonate; allyl ester compounds, such as allyl acetate,allyl propionate, allyl pivalate, allyl benzoate, allyl cinnamate,diallyl carbonate, allylmethyl carbonate, and allylphenyl carbonate;unsaturated group-containing ether compounds, such as vinyl phenylether, vinyl ethyl ether, divinyl ether, trimethylolpropane monovinylether, trimethylolpropane divinyl ether, trimethylolpropane trivinylether, pentaerythritol monovinyl ether, pentaerythritol divinyl ether,pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether,1,4-butanediol monovinyl ether, 1,4-butanediol divinyl ether, ethyleneglycol monovinyl ether, ethylene glycol divinyl ether, propylene glycolmonovinyl ether, propylene glycol divinyl ether, polyethylene glycolmonovinyl ether, polyethylene glycol divinyl ether, polypropylene glycolmonovinyl ether, polypropylene glycol divinyl ether, vinyl glycidylether, allyl phenyl ether, allyl ethyl ether, diallyl ether, vinyl allylether, trimethylolpropane monoallyl ether, trimethylolpropane diallylether, trimethylolpropane triallyl ether, pentaerythritol monoallylether, pentaerythritol diallyl ether, pentaerythritol triallyl ether,pentaerythritol tetraallyl ether, 1,4-butanediol monoallyl ether,1,4-butanediol diallyl ether, ethylene glycol monoallyl ether, ethyleneglycol diallyl ether, propylene glycol monoallyl ether, propylene glycoldiallyl ether, polyethylene glycol monoallyl ether, polyethylene glycoldiallyl ether, polypropylene glycol monoallyl ether, polypropyleneglycol diallyl ether, and allyl glycidyl ether; maleimide compounds,such as maleimide, methylmaleimide, ethylmaleimide, propylmaleimide,butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide,stearylmaleimide, phenylmaleimide, and cyclohexylmaleimide; acrylic acidand methacrylic acid; acrolein and methacrolein; cyclopolymerizablecompounds, such as 1,6-heptadiene and diallylammonium salts; and N-vinylpyrrolidone, N-vinyl carbazole, etc. These compounds may be used aloneor in combination. When a copolymer is produced from a plurality ofvinyl monomers, any form may be acceptable, such as a random copolymer,a block copolymer, a graft copolymer, or a combination of these.

Among the vinyl monomers described above, in view of availability andcost, preferred are styrene, α-methylstyrene, vinyl chloride, vinylidenechloride, methacrylate esters, acrylate esters, methacrylic acid,acrylic acid, methacrylamide, acrylamide, methacrylonitrile,acrylonitrile, vinyl acetate, maleic anhydride, and maleimide compounds.In view of the fact that the resultant polymer is excellent in oilresistance, heat resistance, weatherability, and low stainingproperties, more preferred are methacrylate esters and acrylate esters.In view of the fact that a cured composition is flexible when thecomposition of the present invention is cured, particularly preferredare methacrylate esters and acrylate esters which can produce polymerswith a glass transition temperature of 30° C. or less. In view ofavailability and cost, as the acrylate esters which can produce polymerswith a glass transition temperature of 30° C. or less, n-butyl acrylateand tert-butyl acrylate are preferable.

When the vinyl monomer used in the present invention is polymerized, thethiocarbonylthio group-containing compound must be present in thereaction system during polymerization. The addition method for thethiocarbonylthio group-containing compound is not particularly limited.In order to control the molecular weight and the molecular weightdistribution of the polymer and in order to increase the introductionrate of crosslinkable silyl groups, preferably, the thiocarbonylthiogroup-containing compound is dissolved or dispersed in the reactionsystem before polymerization is initiated. For example, in the case ofsolution polymerization, the thiocarbonylthio group-containing compoundis preferably dissolved in a solvent or a vinyl monomer before addition.In the case of water-based polymerization, such as emulsionpolymerization or suspension polymerization, preferably, thethiocarbonylthio group-containing compound is dissolved in a smallamount of solvent before addition, the thiocarbonylthio group-containingcompound is dissolved in a vinyl monomer before addition, or thethiocarbonylthio group-containing compound is preliminarily stirred witha homogenizer or the like before dispersion.

The amount of the thiocarbonylthio group-containing compound used is notparticularly limited. Since the degree of polymerization of theresultant polymer depends on the number of moles of the thiocarbonylthiogroup-containing compound added, the amount of the thiocarbonylthiogroup-containing compound may be calculated based on the required degreeof polymerization or number-average molecular weight of the polymer. Ingeneral, the relationship between the number of moles of thethiocarbonylthio group-containing compound and the degree ofpolymerization of the resultant polymer is represented by the followingequation.Degree of polymerization=(Number of moles of vinyl monomer)/(Number ofmoles of thiocarbonylthio group-containing compound)

Additionally, the number-average molecular weight is calculated bymultiplying the degree of polymerization by the molecular weight of thevinyl monomer.

In the present invention, when a vinyl monomer is radically polymerizedin the presence of a thiocarbonylthio group-containing compound, anymethod commonly used in the art, such as bulk polymerization, solutionpolymerization, emulsion polymerization, suspension polymerization, ormicrosuspension polymerization, may be employed. Among them, in view ofcost and safety, water-based polymerization, such as emulsionpolymerization, suspension polymerization, or microsuspensionpolymerization, is preferred.

In the case of solution polymerization of the vinyl monomers, examplesof solvents which may be used include, but are not limited to,hydrocarbon solvents, such as heptane, hexane, octane, and mineralspirit; ester solvents, such as ethyl acetate, n-butyl acetate, isobutylacetate, ethylene glycol monomethyl ether acetate, and diethylene glycolmonobutyl ether acetate; ketone solvents, such as acetone, methyl ethylketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone;alcohol solvents, such as methanol, ethanol, isopropanol, n-butanol,sec-butanol, and isobutanol; ether solvents, such as tetrahydrofuran,diethyl ether, dibutyl ether, dioxane, ethylene glycol dimethyl ether,and ethylene glycol diethyl ether; and aromatic petroleum solvents, suchas toluene, xylene, benzene, Swasol 310 (manufactured by Cosmo Oil Co.,Ltd.), Swasol 1000 (manufactured by Cosmo Oil Co., Ltd.), and Swasol1500 (manufactured by Cosmo Oil Co., Ltd.). These solvents may be usedalone or in combination. The types and amounts of solvent used may bedetermined in consideration of the solubility of the monomers, thesolubility of the resultant polymer, the polymerization initiatorconcentration and the monomer concentration suitable for achieving asatisfactory reaction rate, the solubility of the thiocarbonylthiogroup-containing compound, effects on human body and environment,availability, cost, etc., and are not particularly limited. Above all,industrially, toluene is preferred in view of availability and cost.

In the present invention, in the case of emulsion polymerization ormicrosuspension polymerization of the vinyl monomers, examples ofemulsifiers which may be used include, but are not limited to, anionicsurfactants, such as fatty acid soap, rosin acid soap, sodiumnaphthalenesulfonate-formalin condensates, sodium alkylbenzenesulfonate, sodium alkysulfate (e.g., sodium dodecylsulfate), ammoniumalkylsulfate, triethanolamine alkylsulfate, sodiumdialkylsulfosuccinate, sodium alkyldiphenylether disulfonate, sodiumpolyoxyethylene alkyl ether sulfate, and sodium polyoxyethylenealkylphenyl ether sulfate; nonionic surfactants, such as polyoxyathylenealkyl ether, polyoxyethylene higher alcohol ether, sorbitan fatty acidester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylenesorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylenefatty acid ester, polyoxyethylene aklylamine, and alkyl alkanolamide;and cationic surfactants, such as alkyltrimethylammonium chloride. Theseemulsifiers may be used alone or in combination. As necessary, acationic surfactant, such as an alkylamine hydrochloride, may be used,or a dispersant for suspension polymerization which will be describedbelow may also be added. The amount of the emulsifier used is usually0.1 to 20 parts by weight based on 100 parts by weight of the monomersused, but is not limited thereto.

In the present invention, in the case of suspension polymerization ofthe monomers, examples of dispersants which may be used include, but arenot limited to, partially saponified poly(vinyl acetate), poly(vinylalcohol), methyl cellulose, carboxymethyl cellulose, gelatin,poly(alkylene oxide), and combinations of anionic surfactants anddispersing agents. These may be used alone or in combination. Theemulsifier used for emulsion polymerization described above may also beused as necessary. The amount of the dispersant used is usually 0.1 to20 parts by weight based on 100 parts by weight of the monomers, but isnot limited thereto.

In the present invention, when vinyl monomers are radically polymerizedin the presence of a thiocarbonylthio group-containing compound, thepolymerization initiator or polymerization initiation method used is notparticularly limited, and any polymerization initiator or polymerizationinitiation method commonly used in the art may be employed. Examples ofpolymerization initiators include, but are not limited to, peroxidepolymerization initiators, such as methyl ethyl ketone peroxide, methylisobutyl ketone peroxide, cyclohexanone peroxide, methyl cyclohexanoneperoxide, isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, lauroylperoxide, benzoyl peroxide, tert-butyl hydroperoxide, cumenehydroperoxide, diisopropylbenzene hydroperoxide, p-menthanehydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-tert-butylperoxide, tert-butyl-α-cumyl peroxide, di-α-cumyl peroxide,1,4-bis[(tert-butylperoxy)isopropyl]benzene,1,3-bis[(tert-butylperoxy)isopropyl]benzene,2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane,2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne,1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane,n-butyl-4,4-bis(tert-butylperoxy)valerate,2,2-bis(tert-butylperoxy)butane, tert-butylperoxy acetate,tert-butylperoxy isobutylate, tert-butylperoxy octoate, tert-butylperoxypivalate, tert-butylperoxy neodecanoate,tert-butylperoxy-3,5,5-trimethyl hexanoate, tert-butylperoxy benzoate,tert-butylperoxy laurate, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane,bis(2-ethylhexyl)peroxy dicarbonate, diisopropylperoxy dicarbonate,di-sec-butylperoxy dicarbonate, di-n-propylperoxy dicarbonate,bis(3-methoxybutyl)peroxy dicarbonate, bis(2-ethoxyethyl)peroxydicarbonate, bis(4-tert-butylcyclohexyl)peroxy dicarbonate,O-tert-butyl-O-isopropylperoxy carbonate, and succinic acid peroxide;azo polymerization initiators, such as2,2′-azobis-(2-amidinopropane)dihydrochloride,2,2′-azobis(dimethylisobutyrate),2,2′-azobis-(4-methoxy-2,4-dimethylvaleronitrile),2,2′-azobis(isobutyronitrile), 1,1′-azobis(cyclohexane-1-carbonitrile),azocumene, 2,2′-azobis(2-methylbutyronitrile),2,2′-azobis-(2,4-dimethylvaleronitrile, 4,4′-azobis(4-cyanovalericacid), 2-(tert-butylazo)-2-cyanopropane,2,2′-azobis(2,4,4-trimethylpentane), and 2,2′-azobis(2-methylpropane);inorganic peroxides, such as potassium persulfate and sodium persulfate;vinyl monomers which thermally generate radical species, such asstyrene; compounds which generate radical species by light, such asbenzoin derivatives, benzophenone, acylphosphine oxide, and photo-redoxsystems; and redox polymerization initiators including sodium sulfite,sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid,ferrous sulfate, or the like, as a reducing agent, and potassiumperoxydisulfate, hydrogen peroxide, tert-butyl hydroperoxide, or thelike, as an oxidizing agent. These polymerization initiators may be usedalone or in combination. It may also be possible to use a polymerizationinitiation system by electron irradiation, X-ray irradiation, radiationirradiation, or the like. With respect to polymerization initiationmethods, the methods described in Moad and Solomon “The Chemistry ofFree Radical Polymerization”, Pergamon, London, 1995, pp. 53-95 may beemployed.

In the present invention, the amount of polymerization initiator used isnot particularly limited. In order to produce a polymer with a narrowmolecular weight distribution, the amount of radical species generatedduring polymerization is preferably 1 mole or less, and more preferably0.5 moles or less, relative to 1 mole of thiocarbonylthio group in thethiocarbonylthio group-containing compound. In order to control theamount of radical species generated during polymerization, in additionto the control of the amount of the polymerization initiator,preferably, temperature is controlled in the case of the polymerizationinitiator which causes thermal dissociation, or the amount of energy iscontrolled in the case of the polymerization initiation system whichgenerates radicals by light or electron beams. Because of ease ofcontrol of polymerization, using a polymerization initiator which causesthermal dissociation, the polymerization reaction is carried outpreferably at temperatures which allow the polymerization initiator tohave a half-life of 0.5 to 50 hours, more preferably at temperatureswhich allow the polymerization initiator to have a half-life of 1 to 20hours, and most preferably at temperatures which allow thepolymerization initiator to have a half-life of 5 to 15 hours.

In the present invention, the molecular weight of the polymer producedby radically polymerizing a vinyl monomer is not particularly limitedand is set depending on the application. In view of balance betweenworkability and heat resistance, strength, or the like, thenumber-average molecular weight (Mn) determined by gel permeationchromatography (GPC) is preferably in the range of 1,000 to 1,000,000,and more preferably in the range of 3,000 to 500,000. In the presentinvention, the molecular weight distribution of the polymer produced byradically polymerizing a vinyl monomer is not particularly limited.Because of excellent workability and strength, the ratio (Mw/Mn) of theweight-average molecular weight (Mw) to the number-average molecularweight (Mn) determined by gel permeation chromatography (GPC) ispreferably 2 or less, and more preferably 1.5 or less.

In the production process of the present invention, the thiocarbonylthiogroups of the thiocarbonylthio group-containing compound are convertedinto mercapto groups. The method for converting thiocarbonylthio groupsinto mercapto groups is not particularly limited. In view of high yield,preferably, a method is employed in which the thiocarbonylthiogroup-containing compound is allowed to react with a processing agentcomposed of a compound selected from the group consisting of bases,acids, ammonia, hydrazine, and amine compounds. Among them, when a base,an acid, or a tertiary amine compound is used, in the presence of water,thiocarbonylthio groups are converted into mercapto groups byhydrolysis. When ammonia, hydrazine, a primary amine compound, or asecondary amine compound is used, the presence of water is not required,which is preferable.

Examples of bases which may be used as processing agents include, butare not limited to, alkali metal hydroxides, such as sodium hydroxide,potassium hydroxide, and lithium hydroxide; alkaline-earth metalhydroxides, such as calcium hydroxide, magnesium hydroxide, bariumhydroxide, and cesium hydroxide; transition metal hydroxides, such asaluminum hydroxide and zinc hydroxide; alkali metal alcoholates, such assodium methylate, sodium ethylate, sodium phenylate, lithium ethylate,and lithium butylate; alkaline-earth metal alcoholates, such asmagnesium methylate and magnesium ethylate; metal hydrides, such assodium hydride, lithium hydride, calcium hydride, lithium aluminumhydride, and aluminum borohydride; and organometallic reagents, such ashydrosulfite, n-butyllithium, tert-butyllithium, ethylmagnesium bromide,and phenylmagnesium bromide. Furthermore, alkali metals, such asmetallic lithium, metallic sodium, and metallic potassium; andalkaline-earth metals, such as metallic magnesium and metallic calciummay also be used. These bases may be used alone or in combination. Amongthem, in view of availability, cost, and reactivity, preferred aresodium hydroxide, potassium hydroxide, lithium hydroxide, calciumhydroxide, magnesium hydroxide, sodium methylate, sodium ethylate,sodium hydride, lithium hydride, metallic lithium, metallic sodium, andmetallic potassium. Because of ease of handling, more preferred aresodium hydroxide, potassium hydroxide, lithium hydroxide, calciumhydroxide, magnesium hydroxide, sodium methylate, and sodium ethylate.

Examples of acids which may be used as processing agents include, butare not limited to, inorganic acids, such as hydrochloric acid, nitricacid, sulfuric acid, phosphoric acid, hydrofluoric acid, hydrobromicacid, fluoroboric acid, chlorosulfonic acid, hydriodic acid, arsenicacid, and silicofluoric acid; organic acids, such as p-toluenesulfonicacid, trifluoromethyl sulfonic acid, acetic acid, trifluoroacetic acid,methylphosphoric acid, ethylphosphoric acid, n-propylphosphoric acid,isopropylphosphoric acid, n-butylphosphoric acid, laurylphosphoric acid,stearylphosphoric acid, 2-ethylhexylphosphoric acid, isodecylphosphoricacid, dimethyldithiophosphoric acid, diethyldithiophosphoric acid,diisopropyldithiophosphoric acid, and phenylphosphonic acid; and strongacidic ion exchange resins and weak acidic ion exchange resins.Furthermore, compounds which show acidity in reaction with a smallamount of water may also be used. Examples of such compounds includeacid anhydrides, such as acetic anhydride, propionic anhydride,trifluoroacetic anhydride, phthalic anhydride, and succinic anhydride;acyl halides; and metal halides, such as titanium tetrachloride,aluminum chloride, and silicon chloride. These acids may be used aloneor in combination. Among them, in view of availability, cost, andreactivity, preferred are hydrochloric acid, nitric acid, sulfuric acid,phosphoric acid, aluminum chloride, titanium tetrachloride,chlorosulfonic acid, p-toluenesulfonic acid, trifluoromethyl sulfonicacid, acetic acid, and trifluoroacetic acid.

The amine compounds used as processing agents include amines and theiranalogues. The amine compounds of the present invention also includeamides and nitrogen-containing aromatic compounds which are analogous toamines. Examples of such amine compounds include, but are not limitedto, hydroxylamine sulfate, hydroxylamine, N-(2-aminoethyl)ethanolamine,N-methylethanolamine, 12-aminododecanoic acid, 3-amino-l-propanol,amine-modified acrylic polymers, allylamine, diallylamine,isopropylamine, diisopropylamine, 3,3′-iminobis(propylamine),ethylamine, diethylamine, triethylamine, 2-ethylhexylamine,3-(2-ethylhexyloxy)propylamine, 3-ethoxypropylamine, diisobutylamine,3-(diethylamino)propylamine, di-2-ethylhexylamine,3-(dibutylamino)propylamine, tert-butylamine, sec-butylamine,n-butylamine, n-propylamine, isopropylamine, 3-(methylamino)propylamine,3-(dimethylamino)propylamine, N-methyl-3,3′-iminobis(propylamine),3-methoxypropylamine, isopropanolamine, N-isopropylacrylamide,iminodiacetic acid, 3,3′-iminodipropionitrile, monoethanolamine,diethanolamine, N-ethylethylenediamine, ethyleneimine, ethylenediamine,diethylenetriamine, triethylenetetramine, tetraethylenepentamine,pentaethylenehexamine, N-carboxy-4,4′-methylenebiscyclohexylamine,carbohydrazides, guanidine hydrochloride, guanidine nitrate, guanidinecarbonate, guanidine phosphate, guanidine sulfamate, aminoguanidinehydrochloride, aminoguanidine bicarbonate, guanylthiourea, guanylureaphosphate, guanylurea sulfate, glycylglycine, 2-chloroethylamine,1,4-diaminobutane, 1,2-diaminopropane, 1,3-diaminopropane,diaminomaleonitrile, cyclohexylamine, cyclopentylamine, dicyandiamide,dicyclohexylamine, N-(3-(dimethylamino)propyl)acrylamide,N-(3-(dimethylamino)propyl)methacrylamide, dimethylamineborane,dimethylhydrazine, N,N′-ethylenebis(stearoamide), amide oleate, amidestearate, N,N′-methylenebis(stearoamide), methylol stearoamide,3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, CTUguanamine, thiocarbohydrazide, thiosemicarbazide, thiourea, dihydrazidedodecanedioate, trans-1,2-cyclohexanediamine, dihydrazide adipate,dihydrazide sebacate, dihydrazide isophthalate, thiourea dioxide,2-hydroxyethylaminopropylamine, isobutylamine, 2-bromoethylamine,hexamethylenediamine, 1,6-hexamethylenebis(N,N-dimethylsemicarbazide),n-hexylamine, polyethyleneimine, formamidine, formamidine acetate,formamide, methacrylamide, monomethylamine, dimethylamine,trimethylamine, N,N′-methylenebis(acrylamide), N-methylolacrylamide,monomethylhydrazine, 3-(lauryloxy)propylamine, acetanilide,acetoacet-o-anisidide, acetoacetanilide, acetoacet-m-xylidide,acetoacet-o-chloroanilide, acetoacet-2,5,-dimethoxyanilide,acetoacet-2,5-dimethoxy-4-chloroanilide, acetoacet-o-toluidide,acetoacet-p-toluidide, o-anisidine, p-anisidine, aniline,p-aminoacetanilide, p-aminobenzoic acid, ethyl p-aminobenzoate ester,2-amino-4-chlorophenol, 2-aminothiazole, 2-aminothiophenol,2-amino-5-nitrobenzonitrile, o-aminophenol, m-aminophenol,p-aminophenol, p-aminobenzaldehyde, 4-aminobenzonitrile, anthranilicacid, 3-isopropoxyaniline, N-ethylaniline, N-ethylene toluenesulfonamide, 2,4-xylidine, 3,4-xylidine, m-xylylenediamine, p-cresidine,dianisidine, 4,4¹-diaminostilbene-2,2′-disulfonic acid,1,4-diaminoanthraquinone, 4,4′-diamino-3,3′-diethyldiphenylmethane,4,4′-diaminobenzanilide, N,N-diethylaniline, diaminodiphenyl ether,diaminonaphthalene, diaminoanthracene, diphenylamine, dibenzylamine,N,N-dimethylaniline, 3,3′-dimethyl-4,4′-diaminodiphenylmethane,sulfanilic acid,1,1,1′,1′-tetramethyl-4,4′-(methylenedi-p-phenylene)disemicarbazide,tobias acid, 2,4,5-trichloroaniline, o-tolidine, o-toluidine,m-toluidine, p-toluidine, m-toluylenediamine, sodium naphthionate,o-nitroaniline, m-nitroaniline, p-nitroaniline, o-nitro-p-chloroaniline,m-nitro-p-toluidine, o-chloro-p-toluidine-m-sulfonic acid,p-hydroxyphenylacetamide, 7-anilino-4-hydroxy-2-naphthalenesulfonicacid, phenylhydrazine, o-phenylenediamine, m-phenylenediamine,p-phenylenediamine, p-phenetidine, phenethylamine, benzylamine,benzophenone hydrazone, mesidine, metanilic acid, N-methylaniline,2-methyl-4-nitroaniline, 2-methyl-4-methoxydiphenylamine,2-amino-5-methylbenzenesulfonic acid, leuco-1,4-diaminoanthraquinone,paramine, p-hydroxyphenylglycine, acetaldehyde ammonia, acetoguanamine,3-amino-1, 2, 4-triazole, 2-aminopyridine, 3-aminopyridine,4-aminopyridine, 1-(2-aminoethyl)piperazine,N-(3-aminopropyl)morpholine, 1-amino-4-methylpiperazine, isocyanuricacid, imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole,2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole,2-phenyl-4-methylimidazole, 1-aminoethyl-2-methylimidazole,1-(cyanoethylaminoethyl)-2-methylimidazole,N-(2-(2-methyl-1-imidazolyl)ethyl)urea,2,4-diamino-6-(2-methyl-1-imidazolylethyl)-1,3,5-triazine,2,4-diamino-6-(2-undecyl-1-imidazolylethyl)-1,3,5-tiazine,2,4-diamino-6-(2-ethyl-4-methyl-1-imidazolylethyl)-1,3,5-tiazine,2-phenyl-4-methyl-5-hydroxymethylimidazole,2-phenyl-4,5-bis(hydroxymethyl)imidazole, an adduct of 2-methylimidazoleand isocyanuric acid, an adduct of 2-phenylimidazole and isocyanuricacid, an adduct of2,4-diamino-6-(2-methyl-1-imidazolylethyl)-1,3,5-triazine andisocyanuric acid, 2-methyl-4-formylimidazole,2-phenyl-4-formylimidazole, 4-formylimidazole,2,4-dimethyl-5-formylimidazole, 2,4-diphenyl-5-formylimidazole,4-methylimidazole, 4-methyl-5-(hydroxymethyl)imidazole,2-amino-4,5-dicyanoimdazole, imidazole-4,5-dicarboxylic acid,3-carbamoyl-2-pyrazine carboxylic acid, imide succinate, quinaldine,quinoline, 1,3-di(4-piperidyl)propane, 2-imidazolidinone,5,5-dimethylhydantoin, 2,5-dimethylpiperazine,cis-2,6-dimethylpiperazine, 3,5-dimethylpyrazole, 2-methyl-4-pyrazolone,5,5′-bi-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-methyl-lH-tetrazole,1,2,3,4-tetrahydroquinoline, bis(aminopropyl)piperazine,1,3-bis(hydrazinocarboethyl)-5-isopropylhydantoin, hydantoin,(hydroxyethyl)piperazine, 2-pipecoline, 3-pipecoline, 4-pipecoline,2-(1-piperazinyl)pyrimidine, piperazine, piperidine, pyrrolidine,pyrrole, phenylpyrazolidone, benzoguanamine, N-methylpiperazine,2-methylpiperazine, 3-methyl-5-pyrazolone,1-methylol-5,5-dimethylhydantoin, melamine, and morpholine. In addition,hindered amine light stabilizers (HALSs) may also be used. Examples ofHALSs include bis(2,2,6,6,-tetramethyl-4-piperidyl)sebacate, SanolLS-770 (manufactured by Sankyo Co., Ltd.), Adekasutabu LA-77(manufactured by Asahi Denka Co., Ltd.), Sumisorb 577 (manufactured bySumitomo Chemical Co., Ltd.), Biosorb 04 (manufactured by Kyodo ChemicalCo., Ltd.), Chimassorb 944LD (manufactured by Ciba Specialty Chemicals),Tinuvin 144 (manufactured by Ciba Specialty Chemicals), AdekasutabuLA-52 (manufactured by Asahi Denka Co., Ltd.), Adekasutabu LA-57(manufactured by Asahi Denka Co., Ltd.), Adekasutabu LA-67 (manufacturedby Asahi Denka Co., Ltd.), Adekasutabu LA-68 (manufactured by AsahiDenka Co., Ltd.), Adekasutabu LA-77 (manufactured by Asahi Denka Co.,Ltd.), Adekasutabu LA-87 (manufactured by Asahi Denka Co., Ltd.), andGoodrite UV-3034 (manufactured by Goodrich Corporation). These may beused alone or in combination.

Among them, when primary amines with a boiling point of 100° C. or less,such as methylamine and ethylamine, or secondary amines with a boilingpoint of 100° C. or less, such as dimethylamine and diethylamine, areused, excess amine compounds can be easily removed by distillation underreduced pressure, and thereby the purification step can be simplified,which is preferable. When HALSs are used, it is not necessary to removeexcess HALSs because they function as stabilizers, and the purificationstep can also be simplified. Furthermore, due to excess HALSs, theresultant polymers have improved weatherability and light resistance.

When ammonia is used, as in primary or secondary amines with a boilingpoint of 100° C. or less, excess ammonia can be removed by distillationunder reduced pressure, and thereby the purification step can besimplified, which is preferable.

However, if a large amount of amine compound remains in the polymer, itreacts with and consumes the compound having a crosslinkable silyl groupand an isocyanato group in each molecule, thus being uneconomical.Therefore, most preferred are ammonia, primary amines with a boilingpoint of 100° C. or less, and secondary amines with a boiling point of100° C. or less, which can easily be removed under reduced pressure.

In the reaction for converting thiocarbonylthio groups into mercaptogroups, the amount of the processing agent used is not particularlylimited. When a base or acid is used as the processing agent, in view ofease of handling and reactivity, the amount used is preferably 0.01 to100 parts by weight, more preferably 0.05 to 50 parts by weight, andmost preferably 0.1 to 30 parts by weight based on 100 parts by weightof the vinyl polymer. When ammonia, hydrazine, or an amine compound isused as the processing agent, because of a high introduction rate ofmercapto groups, the amount of ammonia, hydrazine, or amine compound ispreferably 0.5 to 1,000 moles, and more preferably 1 to 500 moles, basedon 1 mole of thiocarbonylthio group.

In the present invention, when the thiocarbonylthio group-containingvinyl polymer is treated with the processing agent, the reactionconditions are not particularly limited. For example, a method in whichthe polymer is dissolved in an organic solvent, and the processing agentis added thereto; a method in which the processing agent is added to awater-based dispersion or emulsion; or a method in which the processingagent is directly added to the solid or molten polymer itself may beemployed. The treatment temperature is not particularly limited. In viewof reactivity and stability of the polymer, the treatment temperature ispreferably −50° C. to 300° C., and more preferably −10° C. to 200° C.

A mercapto-group containing vinyl polymer is thereby produced.

In the production process of the present invention, using the mercaptogroups of the mercapto group-containing vinyl polymer prepared by themethod described above or the like, the polymer and a compound having acrosslinkable silyl group and an isocyanato group in each molecule arecoupled.

The compound having a crosslinkable silyl group and an isocyanato groupin each molecule used in the present invention is not particularlylimited. In view of availability and cost, the compound having acrosslinkable silyl group and an isocyanato group in each molecule ispreferably a compound represented by general formula (4):

 OCN—(CH₂)_(n)—Si(R⁴)_(3-a)(X)_(a)  (4)

(wherein R⁴ is an alkyl group, a substituted alkyl group, an aryl group,a substituted aryl group, an aralkyl group, a substituted aralkyl group,or a triorganosiloxy group; X is a hydroxyl group or a hydrolyzablegroup; n is an integer of 3 or more: a is 1, 2, or 3; when a is 1, twoR⁴s may be the same or different; and when a is 2 or 3, two or three Xsmay be the same or different). In view of availability, preferably, R⁴has 1 to 20 carbon atoms, and n is 3 to 500.

Specific examples of the hydrolyzable group X in general formula (4)include, but are not limited to, a hydrogen atom, a halogen atom, analkoxy group, an acyloxy group, a ketoximate group, an amino group, anamide group, an acid amide group, an aminooxy group, a mercapto group,and an alkenyloxy group. Among them, an alkoxy group is preferredbecause of its mild hydrolyzability, ease of handling, and lowreactivity with the isocyanato group. In view of availability andreactivity, an alkoxy group having 6 or less carbon atoms, such asmethoxy, ethoxy, or phenoxy, is more preferred.

The compounds having a crosslinkable silyl group and an isocyanato groupin each molecule used in the present invention may be used alone or incombination. Among these compounds, in view of high stability,availability, and cost, more preferred areγ-isocyanatopropyltrimethoxysilane,γ-isocyanatopropyldimethoxymethylsilane,γ-isocyanatopropyltriethoxysilane, andγ-isocyanatopropyldiethoxymethylsilane.

The amount of the compound having a crosslinkable silyl group and anisocyanato group in each molecule used is not particularly limited. Inview of the fact that satisfactory physical properties are exhibitedwhen a curable composition containing the coupled polymer is cured, theamount used, on the basis of the isocyanato group, is preferably 0.4 to50 moles, more preferably 0.5 to 30 moles, and most preferably 0.8 to 20moles, relative to 1 mole of the mercapto group of the polymer. Evenwhen the compound having a crosslinkable silyl group and an isocyanatogroup in each molecule is used in excess relative to the mercapto groupof the polymer, it is not particularly necessary to remove or purify theexcess compound because the excess compound acts as a silane couplingagent when a curable composition containing the polymer is produced.

In the production process of the present invention, mercapto groups ofthe polymer and isocyanato groups of the compound having a crosslinkablesilyl group and an isocyanato group in each molecule are coupled to formthiourethane bonds (—SC(═O)NH— or —OC(═S)NH—), and thereby crosslinkablesilyl groups are introduced into the polymer. In the reaction, in orderto improve the reaction efficiency, a urethane formation catalyst may beused as necessary.

Any urethane formation catalyst which is commonly used in the art may beused in the present invention. For example, the catalysts cited inPolyurethanes: Chemistry and Technology, Part I, Table 30, Chapter 4,Saunders and Frisch, Interscience Publishers, New York, 1963 may beused, but usable catalysts are not limited thereto. These may be usedalone or in combination. In view of high catalytic activity, preferredexamples of urethane formation catalysts include tin-based urethaneformation catalysts, such as tin octylate, tin stearate, dibutyltindioctoate, dibutyltin dioleylmaleate, dibutyltin dibutylmaleate,dibutyltin dilaurate,1,1,3,3-tetrabutyl-1,3-dilauryloxycarbonyldistannoxane, dibutyltindiacetate, dibutyltin diacetylacetonate, dibutyltinbis(o-phenylphenoxide), dibutyltin oxide, dibutyltinbis(triethoxysilicate), dibutyltin distearate, dibutyltinbis(isononyl-3-mercaptopropionate), dibutyltin bis(isooctylthioglycolate), dioctyltin oxide, dioctyltin dilaurate, dioctyltindiacetate, and dioctyltin diversatate. In view of storage stability,more preferred are tin-based urethane formation catalysts containingsulfur atoms, such as dibutyltin bis(isononyl-3-mercaptopropionate) anddibutyltin bis(isooctyl thioglycolate).

The amount of the urethane formation catalyst used in the presentinvention is not particularly limited, but is preferably 0.0001 to 0.5parts by weight, and more preferably 0.001 to 0.1 parts by weight, basedon 100 parts by weight of the vinyl polymer. If the amount is less than0.0001 parts by weight, sufficient reactivity may not be obtained. Ifthe amount exceeds 0.5 parts by weight, physical properties, such asheat resistance, weatherability, hydrolysis resistance, and storagestability, of the resultant vinyl polymer, curable composition, andcured composition obtained by curing the composition may be degraded.

In the present invention, when the mercapto groups of the polymer andthe isocyanato groups of the compound having a crosslinkable silyl groupand an isocyanato group in each molecule are coupled, a solvent may beused in order to homogeneously dissolve the catalyst or the compounds,or in order to improve the temperature control of the reaction system orthe reaction efficiency. Examples of solvents which may be used forthese purposes include, but are not limited to, hydrocarbons, such ashexane, cyclohexane, ethylcyclohexane, heptane, octane, dodecane,benzene, toluene, xylene, and dodecylbenzene; halogenated hydrocarbons,such as chloroform, methylene chloride, 1,2-dichloroethane,chlorobenzene, and o-dichlorobenzene; and ethers, such as diethyl ether,tetrahydrofuran, dioxane, and ethylene glycol dimethyl ether. These maybe used alone or in combination. In order to prevent side reactionsassociated with the isocyanato group and crosslinkable silyl group, thewater content of the solvent used is preferably 500 ppm or less, andmore preferably 200 ppm or less.

A crosslinkable silyl group-containing polymer of the present inventionis thereby produced. Scheme 1 illustrates a reaction scheme in the casewhen a thiocarbonylthio group-containing compound represented by generalformula (3) is used.

Crosslinkable silyl group-containing polymers produced in accordancewith the present invention can be used for various purposes depending ontheir physical properties. Examples of applications include, but are notlimited to, sealants, adhesives, pressure-sensitive adhesives,elastomeric adhesives, hardenable pressure-sensitive adhesives, hot-meltadhesives, reactive hot-melt adhesives, reactive thermoplasticelastomers, reactive synthetic rubbers, and reactive thermoplasticresins; various molded objects, such as hoses, sheets, films, flatplates, corrugated plates, pipes, sashes, shoe soles, sporting goods,textiles, toys, automobile components, gaskets, packings, foams,synthetic marbles, resins alternative to glass, containers, bottles,bottle caps, artificial hair, artificial skin, pillars, wall materials,floor materials, grips, doors, electric appliance cases, lenses, opticalcomponents, electric circuit boards, electronic components, and wirecoverings; modifiers, such as asphalt modifiers, resin modifiers, rubbermodifiers, and cement modifiers; paint and coating materials; andpotting materials for electronic components.

Among the applications described above, when elastomeric properties arerequired in the resultant cured compositions, such as in sealants,adhesives, and pressure-sensitive adhesives, crosslinkable silylgroup-containing polymers having a glass transition temperature of 30°C. or less are preferred. Preferably, such a crosslinkable silylgroup-containing polymer contains, as a component, an n-butyl acrylatehomopolymer or a copolymer containing n-butyl acrylate as a principalconstituent, or the like, in the molecule. In view of high strength ofthe resultant cured composition, the crosslinkable silylgroup-containing polymer preferably has crosslinkable silyl groups atboth ends.

Among the applications described above, when crosslinkable silylgroup-containing polymers are used for reactive hot-melt adhesives,reactive thermoplastic elastomers, and the like, preferred crosslinkablesilyl group-containing polymers are those which are cured after moldingor bonding to produce cured compositions having excellent heatresistance and compression set characteristics while exhibiting physicalproperties of thermoplastic elastomers, e.g., excellent moldability. Inorder to prepare such a crosslinkable silyl group-containing polymer,for example, crosslinkable silyl groups are introduced into athermoplastic elastomer having a hard segment and a soft segment, whichis commonly used in the art. Examples of such thermoplastic elastomersinclude, but are not limited to, methyl methacrylate-n-butylacrylate-methyl methacrylate triblock copolymers,styrene-butadiene-styrene triblock copolymers, methylmethacrylate-n-butyl acrylate diblock copolymers, styrene-butadienediblock copolymers, and vinyl chloride-acrylonitrile multiblockcopolymers.

Among the applications described above, when crosslinkable silylgroup-containing polymers are used for reactive synthetic rubbers, asthe crosslinkable silyl group-containing polymer, for example, polymersproduced by introducing crosslinkable silyl groups into syntheticrubbers which are commonly used in the art are used. Examples ofsynthetic rubbers include, but are not limited to, polybutadiene,poly(vinyl chloride), polyisoprene, vinyl chloride-vinyl acetatecopolymers, vinyl chloride-acrylonitrile copolymers, poly(n-butylacrylate), methyl methacrylate-butyl acrylate copolymers, butylacrylate-butadiene-styrene copolymers, ethylene-propylene-dienecopolymers, and methyl methacrylate-butadiene-styrene copolymers. Thecrosslinkable silyl group-containing polymers (reactive syntheticrubbers) prepared by using such synthetic rubbers have superior heatresistance, heat stability, and compression set characteristics comparedto conventional synthetic rubbers.

Among the applications described above, when crosslinkable silylgroup-containing polymers are used for reactive thermoplastic resins, asthe crosslinkable silyl group-containing polymer, for example, polymersproduced by introducing crosslinkable silyl groups into thermoplasticresins which are commonly used in the art, such as vinyl chlorideresins, styrene resins, and acrylic resins, are used, but not limitedthereto. The crosslinkable silyl group-containing polymers (reactivethermoplastic resins) prepared by using such thermoplastic resins haveexcellent heat resistance, heat stability, and compression setcharacteristics along with the advantage of the conventionalthermoplastic resins, e.g., excellent moldability.

In the curable composition of the present invention containing thecrosslinkable silyl group-containing polymer, in order to adjust variousphysical properties, at least one type of additives may be compounded asnecessary. Examples of additives include plasticizers,thixotropy-improving agents, heat resistance-improving agents,stabilizers, antioxidants, ultraviolet absorbers, hindered amine lightstabilizers (HALSs), antistatic agents, fire retardants, colorants,blowing agents, lubricants, mildewproofing agents, nucleating additives,vulcanization accelerators, aging resisters, vulcanizing agents,antiscorching agents, peptizers, tackifiers, latex coagulants,processing aids, inorganic fillers, silane coupling agents, and rubbermaterials. Optimum additives may be selected depending on the type andcomposition of the crosslinkable silyl group-containing polymer, theapplication of the cured composition, etc.

The curable compositions of the present invention containing thecrosslinkable silyl group-containing polymers may contain condensationcatalysts as necessary. In particular, when the curable compositions areused as moisture-curing compositions, such as sealants, adhesives,pressure-sensitive adhesives, paint, reactive hot-melt adhesives,reactive thermoplastic resins, and reactive thermoplastic elastomers,condensation catalysts are preferably incorporated into the curablecompositions. A condensation catalyst is a compound which catalyzes thereaction in which crosslinkable silyl groups are coupled with each otherto form a siloxane bond. Examples of condensation catalysts include, butare not limited to, titanate esters, such as tetrabutyl titanate andtetrapropyl titanate; organotin compounds, such as dibutyltin dilaurate,dibutyltin bisacetylacetonate, dibutyltin oxide, dibutyltin dimethoxide,dibutyltin maleate, dibutyltin diacetate, tin octylate, and tinnaphthenate; lead compounds, such as lead octylate; amine compounds,such as butylamine, octylamine, dibutylamine, monoethanolamine,diethanolamine, triethanolamine, diethylenetriamine,triethylenetetramine, oleylamine, cyclohexylamine, benzylamine,diethylaminopropylamine, xylylenediamine, triethylenediamine, guanidine,diphenylguanidine, 2,4,6-tris(dimethylaminomethyl)phenol, morpholine,N-methylmorpholine, and 1,3-diazabicyclo[5.4.6]undecene-7; carboxylatesalts of these amine compounds; low-molecular-weight polyamide resinsprepared from an excess polyamine and a polybasic acid; reactionproducts from an excess polyamine and an epoxy compound; and aminogroup-containing silane coupling agents, such asγ-aminopropyltrimethoxysilane andN-(β-aminoethyl)aminopropylmethyldimethoxysilane. These condensationcatalysts may be used alone or in combination. Among these condensationcatalysts, organotin compounds are preferred because of high activity.

In the curable composition of the present invention, the amount ofcondensation catalyst used is not particularly limited. In view ofreactivity, preferably, the condensation catalyst is used in an amountof 0 to 10% by weight relative to the crosslinkable silylgroup-containing polymer. When a urethane formation catalyst is usedduring the production of the crosslinkable silyl group-containingpolymer, a condensation catalyst is not necessarily required because theurethane formation catalyst also acts as a condensation catalyst.

The curable composition of the present invention may be provided in anyform. Typical examples of curable compositions include a one-partcurable composition in which all the components of the composition arepreliminarily mixed and hermetically sealed, and which is cured bymoisture in air after being applied to a desired place; and a two-partcurable composition in which a mixture of components, such as acrosslinkable silyl group-containing polymer, a curing catalyst, andwater, and a curing agent are separately prepared, and mixed before use.

In accordance with the present invention, it is possible to simplyprepare crosslinkable silyl group-containing polymers having desiredpolymer components using thiocarbonylthio group-containing compounds.Consequently, it is possible to prepare crosslinkable silylgroup-containing polymers having desired properties and various curablecompositions. Examples of applications of the resultant curablecompositions include, but are not limited to, sealants, adhesives,pressure-sensitive adhesives, elastomeric adhesives, hardenablepressure-sensitive adhesives, hot-melt adhesives, reactive hot-meltadhesives, reactive thermoplastic elastomers, reactive syntheticrubbers, and reactive thermoplastic resins; various molded objects, suchas hoses, sheets, films, flat plates, corrugated plates, pipes, sashes,shoe soles, sporting goods, textiles, toys, automobile components,gaskets, packings, foams, synthetic marbles, resins alternative toglass, containers, bottles, bottle caps, artificial hair, artificialskin, pillars, wall materials, floor materials, grips, doors, electricappliance cases, lenses, optical components, electric circuit boards,electronic components, and wire coverings; modifiers, such as asphaltmodifiers, resin modifiers, rubber modifiers, cement modifiers, andsurface modifiers; paint and coating materials; silane coupling agents,macromonomers used for resin modification, polymer production, resinproduction, adhesive modification, pressure-sensitive adhesivemodification, etc., and potting materials for electronic components.

BEST MODE FOR CARRYING OUT THE INVENTION

While the present invention will be described based on the examplesbelow, it is to be understood that the invention is not limited thereto.

In the description below, the weight-average molecular weight (Mw),number-average molecular weight (Mn), and molecular weight distribution(Mw/Mn) were determined by gel permeation chromatography (GPC). In theGPC, chloroform was used as an eluent, and a polystyrene gel column wasused. The analysis was carried out on the basis of polystyrene.

Izod impact strength was measured according to ASTM D256-56, usingV-notched specimens, and average values measured at n=5 were calculated.Gardner strength was measured according to ASTM D3029-84-GB, using a 700g weight, at 23° C., and at n=40. Melt viscosity was measured accordingto JIS K-7199, using a capillary rheometer, at a shear rate of 1,216s⁻¹. In a spiral flow test, square spiral molded objects with athickness of 3 mm were injection-molded at a cylinder temperature of250° C., a die temperature of 70° C., and an injection pressure of 608kgf/cm², and molding fluidity was evaluated based on the length (mm)thereof.

EXAMPLE 1

Into a 1 L reactor equipped with an agitator, a thermometer, a nitrogengas inlet tube, and a reflux condenser tube, was placed 181 g of n-butylacrylate as a vinyl monomer, 40 mg of1,1′-azobis(1-cyclohexanecarbonitrile) as a polymerization initiator,635 mg of compound represented by formula (5):

as a thiocarbonylthio group-containing compound, and 300 mL of tolueneas a solvent, and the reactor was nitrogen-purged. The reaction solutionwas heated at 90° C. for 5 hours while being stirred. Toluene wasremoved from the reaction solution by distillation under reducedpressure. Thereby, 110 g of polymer (Mw=77,000, Mn=56,900, andMw/Mn=1.35) was produced. ¹H NMR measurement confirmed thatthiocarbonylthio groups were introduced into both ends of the polymer,and the introduction rate was 93% on the both-ends basis.

The resultant poly(n-butyl acrylate) having thiocarbonylthio groups atboth ends (110 g) was dissolved in 400 mL of toluene, and 30 g ofmonoethylamine as an amine compound was added thereinto, followed bystirring at 10° C. for 5 hours. The remaining monoethylamine and toluenewere removed by distillation under reduced pressure, and a polymer wasthereby produced. ¹H NMR measurement confirmed that the resultantpolymer was poly(n-butyl acrylate) having mercapto groups at both ends,and the introduction rate of mercapto groups was 90% on the both-endsbasis.

The resultant poly(n-butyl acrylate) having mercapto groups at both ends(105 g) was dissolved in 400 mL of dehydrated toluene, and in a nitrogenatmosphere, 10 mg of dibutyltin bis(isooctyl thioglycolate) as aurethane formation catalyst and 800 mg ofγ-isocyanatopropyldimethoxymethylsilane as a compound having acrosslinkable silyl group and an isocyanato group in each molecule wereadded thereinto, followed by stirring at 80° C. for 8 hours. Toluene wasremoved by distillation under reduced pressure, and poly(n-butylacrylate) having dimethoxymethylsilyl groups at both ends was therebyproduced.

Dibutyltin dimethoxide (1 part by weight) as a curing catalyst was mixedinto 100 parts by weight of the resultant poly(n-butyl acrylate) havingdimethoxymethylsilyl groups at both ends, and the mixture was pouredinto a slab mold, deaerated under reduced pressure, and left to stand inair at room temperature for 4 days. A cured sheet which was uniform andelastomeric was thereby obtained. A No. 2(⅓) dumbbell specimen wasformed by die-cutting the cured sheet, and a tensile test was carriedout using Autograph manufactured by Shimadzu Corp. (measurementconditions: 23° C., 200 mm/min). The tensile strength at break was 0.45MPa, and the elongation at break was 29%.

Next, in the same manner as that described above, 1 part by weight ofdibutyltin dimethoxide was mixed into 100 parts by weight ofpoly(n-butyl acrylate) having dimethoxymethylsilyl groups at both ends.The resultant mixture was applied to the surface of a marble plate at athickness of 1 to 2 mm, to which another marble plate was bonded. Afterapplication, curing was performed by heating at 50° C. for 20 hours.Using a sunshine weatherometer (manufactured by Suga Test InstrumentsCo., Ltd.), ultraviolet irradiation was performed for 1,000 hours. As aresult, crazing, deformation such as peeling, and coloration were notobserved, adhesion failure did not occur, or staining to the stone wasnot observed.

EXAMPLE 2

Into a 1 L reactor equipped with an agitator, a thermometer, a nitrogengas inlet tube, and a reflux condenser tube, was placed 181 g of n-butylacrylate as a vinyl monomer, 40 mg of1,1′-azobis(1-cyclohexanecarbonitrile) as a polymerization initiator,1.40 g of compound represented by formula (5):

as a thiocarbonylthio group-containing compound, and 300 mL of tolueneas a solvent, and the reactor was nitrogen-purged. The reaction solutionwas heated at 90° C. for 40 hours while being stirred. The reactionliquid was sampled, and GPC measurement confirmed that a polymer(Mw=56,500, Mn=41,100, and Mw/Mn=1.37) was produced. Furthermore, ¹H NMRmeasurement confirmed that thiocarbonylthio groups were introduced intoboth ends of the polymer, and the introduction rate was 90% on theboth-ends basis.

Next, 30 g of diethylamine as an amine compound was added thereinto,followed by stirring at 30° C. for 8 hours. The remaining diethylamineand toluene were removed by distillation under reduced pressure, and apolymer was thereby produced. ¹H NMR measurement confirmed that theresultant polymer was poly(n-butyl acrylate) having mercapto groups atboth ends, and the introduction rate of mercapto groups was 89% on theboth-ends basis.

The resultant poly(n-butyl acrylate) having mercapto groups at both ends(150 g) was dissolved in 300 mL of toluene, and in a nitrogenatmosphere, 12 mg of dibutyltin bis(isooctyl thioglycolate) as aurethane formation catalyst and 1.35 g ofγ-isocyanatopropyldimethoxymethylsilane as a compound having acrosslinkable silyl group and an isocyanato group in each molecule wereadded thereinto, followed by stirring at 80° C. for 8 hours. Toluene wasremoved by distillation under reduced pressure, and poly(n-butylacrylate) having dimethoxymethylsilyl groups at both ends was therebyproduced.

Dibutyltin bisacetylacetonate U-220 (manufactured by Nitto Kasei Co.,Ltd.) (1 part by weight) as a curing catalyst and water (0.5 parts byweight) were mixed into 100 parts by weight of the resultantpoly(n-butyl acrylate) having dimethoxymethylsilyl groups at both ends,and the mixture was poured into a slab mold and deaerated under reducedpressure. After the molded product was left to stand at room temperaturefor 2 days, heating was performed at 50° C. for 20 hours. A cured sheetwhich was uniform and elastomeric was thereby obtained. A No. 2(⅓)dumbbell specimen was formed by die-cutting the cured sheet, and atensile test was carried out using Autograph manufactured by ShimadzuCorp. (measurement conditions: 23° C., 200 mm/min). The tensile strengthat break was 0.47 MPa, and the elongation at break was 35%.

EXAMPLE 3

Into a 1 L reactor equipped with an agitator, a thermometer, a nitrogengas inlet tube, a reflux condenser tube, and a dropping funnel, wasplaced 410 mg of sodium dodecylsulfate as an emulsifier and 400 g ofdistilled water, and the reactor was nitrogen-purged while the mixturewas being stirred at 80° C. Next, 1.08 g of compound represented byformula (6):

as a thiocarbonylthio group-containing compound, which was dissolved in25.6 g of n-butyl acrylate as a vinyl monomer, was added into thereactor, followed by stirring at 80°C. for 20 minutes under nitrogenflow. As a polymerization initiator, 432 mg of4,4′-azobis(4-cyanovaleric acid) together with 25 g of distilled waterwas further added thereinto. Stirring was performed at 80° C. for 30minutes, and then a mixed solution of 51.3 g of n-butyl acrylate and52.1 g of 2-methoxyethyl acrylate was dripped from the dropping funnelfor over 1.5 hours. After dripping was completed, the mixture wasstirred at 80° C. for 4 hours, and the emulsion was then cooled to roomtemperature. A salting-out method was performed, followed by filtrationand washing. Thereby, an n-butyl acrylate-2-methoxyethyl acrylate randomcopolymer was produced. GPC analysis and ¹H NMR analysis confirmed thatin the polymer, Mw=64,700, Mn=56,300, and Mw/Mn=1.15 and that theintroduction rate of thiocarbonylthio groups was 94% on the both-endsbasis.

The polymer having thiocarbonylthio group at both ends (80 g) wasdissolved in 100 mL of toluene, and 10 g of monoethylamine as an aminecompound was added thereto, followed by stirring at 5° C. for 10 hours.Thereby, an n-butyl acrylate-2-methoxyethyl acrylate random copolymerhaving mercapto groups at both ends was produced.

After the remaining monoethylamine and toluene were removed bydistillation under reduced pressure, the polymer was dissolved in 150 mLof dehydrated tetrahydrofuran, and 4 mg of dibutyltin bisacetylacetonateU-220 (manufactured by Nitto Kasei Co., Ltd.) as a urethane formationcatalyst which was also usable as a curing catalyst and 550 mg ofγ-isocyanatopropyldimethoxymethylsilane as a compound having acrosslinkable silyl group and an isocyanato group in each molecule wereadded thereinto. Stirring was performed at 80° C. for 5 hours.Tetrahydrofuran was removed by distillation, and an n-butylacrylate-2-methoxyethyl acrylate random copolymer havingdimethoxymethylsilyl groups at both ends was thereby produced.

The resultant copolymer was poured into a slab mold and deaerated underreduced pressure. After the molded product was left to stand at roomtemperature for 7 days, heating was performed at 50° C. for 10 hours. Acured sheet which was uniform and elastomeric was thereby obtained. ANo. 2(⅓) dumbbell specimen was formed by die-cutting the cured sheet,and a tensile test was carried out using Autograph manufactured byShimadzu Corp. (measurement conditions: 23° C., 200 mm/min). The tensilestrength at break was 0.41 MPa, and the elongation at break was 64%.

EXAMPLE 4

Styrene (45.1 g) as a vinyl monomer and a compound represented byformula (7):

(273 mg) as a thiocarbonylthio group-containing compound were weighedand placed into a 200 mL reactor equipped with an agitator, athermometer, a nitrogen gas inlet tube, and a reflux condenser tube, andthe reactor was nitrogen-purged. Stirring was performed at 100° C. for20 hours, and sampling was performed. GPC measurement confirmed that apolymer (MW=35,500, Mn=25,800, and Mw/Mn=1.38) was produced. The polymerwas a star polymer with four arms, and it was confirmed by ¹H NMRmeasurement that the polymer had a thiocarbonylthio group at each end.The introduction rate of thiocarbonylthio groups was 78% on the all-endsbasis.

Toluene (100 mL) and monomethylamine (2.5 g) as an amine compound wereadded thereinto, followed by stirring at 0° C. for 15 hours. The solventwas removed by distillation under reduced pressure, and thereby a starpolymer with four arms was produced. ¹H NMR measurement confirmed thatthe polymer had a mercapto group at each end. The introduction rate ofmercapto groups was 72% on the all-ends basis.

After monomethylamine was removed by distillation under reducedpressure, 30 mL of toluene was added, and in a nitrogen atmosphere, 5 mgof dibutyltin bis(isooctyl thioglycolate) as a urethane formationcatalyst and 1.10 g of γ-isocyanatopropyltrimethoxysilane as a compoundhaving a crosslinkable silyl group and an isocyanato group in eachmolecule were added thereinto, followed by stirring at 80° C. for 8hours. Toluene was removed by distillation under reduced pressure, andthereby star polystyrene having a trimethoxysilyl group at each end wasproduced.

The resultant star polystyrene having a trimethoxysilyl group at eachend was moldable as in conventional polystyrene resins. The resultantmolded object had a higher heat distortion temperature than that of theconventional polystyrene resin by 30° C. or more, thus being excellentin heat resistance and heat stability.

EXAMPLE 5

Into a 1 L reactor equipped with an agitator, a thermometer, a nitrogengas inlet tube, a reflux condenser tube, and a dropping funnel, wasplaced 7.5 g of compound represented by formula (6):

as a thiocarbonylthio group-containing compound, 20 g of acrylonitrileand 40 g of styrene as vinyl monomers, and 11 g of2,2′-azobis(isobutyronitrile) as a polymerization initiator.Furthermore, into the dropping funnel was placed 500 g of toluene as asolvent and 130 g of acrylonitrile and 260 g of styrene as vinylmonomers, and the reactor was nitrogen-purged.

The solution in the reactor was stirred at 70° C. for 1 hour, and thenthe solution of acrylonitrile and styrene was dripped from the droppingfunnel for over 5 hours. After dripping was completed, stirring wasfurther performed at 70° C. for 10 hours. Sampling was performed, andGPC analysis and ¹H NMR analysis confirmed that a thiocarbonylthiogroup-terminated acrylonitrile-styrene random copolymer (MW=27,000,Mn=22,300, and Mw/Mn=1.21) was produced. The compositional ratio was asfollows: acrylonitrile:styrene=34:66 (weight ratio). The introductionratio of thiocarbonylthio groups was 93% on the end basis.

The solution was cooled to room temperature, and 50 g of diethylamine asan amine compound was added thereinto, followed by stirring at roomtemperature for 10 hours. The excess diethylamine was removed bydistillation under reduced pressure, and the reaction liquid was pouredinto 4 L of methanol to precipitate a polymer. The resultant polymer wasdried under reduced pressure and then dissolved in 500 mL of dehydratedtoluene. In a nitrogen atmosphere, 20 mg of dibutyltin bis(isooctylthioglycolate) as a urethane formation catalyst and 6.0 g ofγ-isocyanatopropyldimethoxymethylsilane as a compound having acrosslinkable silyl group and an isocyanato group in each molecule wereadded thereinto, followed by stirring at 50° C. for 6 hours. Toluene wasremoved by distillation under reduced pressure, and anacrylonitrile-styrene random copolymer having dimethoxymethylsilylgroups at both ends was thereby produced. The copolymer was moldable asa thermoplastic resin.

EXAMPLE 6

A mixture of 100 parts by weight of vinyl chloride resin S1008(manufactured by Kaneka Corporation), 2.5 parts by weight of dibutyltinmaleate as a stabilizer, 0.5 parts by weight of Hoechst Wax E(manufactured by Hoechst Japan Ltd.) as a lubricant, 2.0 parts by weightof PA-20 (manufactured by Kaneka Corporation) as a processing aid, and3.0 parts by weight of titanium oxide as a coloring agent was compoundedwith 12 parts by weight of the crosslinkable silyl group-containingpolymer produced in Example 1 and 0.2 parts by weight of dibutyltinbisacetylacetonate. The resultant composition was roll-kneaded at apreset temperature of 180° C. for 5 minutes and formed into a sheet. Theresultant sheet was thermopress-molded at a preset temperature of 190°C. to form a molded object with a thickness of 5 mm for evaluatingphysical properties. The Izod impact strength measured at 23° C. isshown in Table 1 below.

EXAMPLES 7 TO 10

Molded objects were formed as in Example 6 except that crosslinkablesilyl group-containing polymers produced in Examples 2 to 5 were used,and Izod impact strength was measured. The results thereof are shown inTable 1.

COMPARATIVE EXAMPLE 1

A similar molded object was formed without compounding the crosslinkablesilyl group-containing polymer in Example 5, and Izod impact strengthwas measured. The results thereof are shown in Table 1.

TABLE 1 Izod impact Crosslinkable silyl strength group-containingpolymer (kJ/m²) Example 6 Example 1 14 Example 7 Example 2 15 Example 8Example 3 12 Example 9 Example 4 11 Example 10 Example 5 13 Comparative—  3 Example 1

As is evident from Table 1, the crosslinkable silyl group-containingpolymers of the present invention are highly effective in improvingimpact resistance as resin modifiers.

EXAMPLE 11

A methacrylic resin, PARAPET G1000 (manufactured by Kuraray Co., Ltd.)(84 parts by weight) was compounded with 16 parts by weight of thecrosslinkable silyl group-containing polymer produced in Example 1 and0.5 parts by weight of dibutyltin dimethoxide. Using a vent-typetwin-screw extruder (32 mm, L/D=25.5), the resultant composition wasextrusion-kneaded at a preset temperature of 230° C. and pelletized. Theresultant pellets were dried at 80° C. for 15 hours, and injectionmolding was then performed at a preset temperature of 230° C. A moldedplate object (120×120×3 mm) for evaluating physical properties wasproduced. The Gardner strength of the molded object is shown in Table 2below.

EXAMPLES 12 AND 13

Molded objects were formed as in Example 11 except that thecrosslinkable silyl group-containing polymers produced in Examples 2 and3 were used, and Gardner impact strength was measured. The resultsthereof are shown in Table 2.

COMPARATIVE EXAMPLE 2

A molded object was formed as in Example 11 without compounding thecrosslinkable silyl group-containing polymer, and Gardner strength wasmeasured. The results thereof are shown in Table 2.

TABLE 2 Gardner Crosslinkable silyl strength group-containing polymer(kg · cm) Example 11 Example 1 18 Example 12 Example 2 19 Example 13Example 3 19 Comparative —  9 Example 2

As is evident from Table 2, when the crosslinkable silylgroup-containing polymers of the present invention are used as resinmodifiers, impact resistance is greatly improved.

EXAMPLE 14

A polycarbonate resin, LEXAN 141R-111 (manufactured by GE PlasticsJapan, Ltd.), (95 parts by weight) as a thermoplastic resin, and TopanolCA (manufactured by Lipre Co., Ltd.)(0.3 parts by weight) andAdekasutabu PEP-36 (manufactured by Asahi Denka Co., Ltd.) (0.3 parts byweight) as stabilizers were prepared and compounded with 5 parts byweight of the crosslinkable silyl group-containing polymer produced inExample 1 and 0.1 parts by weight of dibutyltin diacetate. Using avent-type twin-screw extruder (32 mm, L/D=25.5), the resultantcomposition was extrusion-kneaded at a preset temperature of 280° C. andpelletized. The resultant pellets were dried at 80° C. for 15 hours, andinjection molding was then performed at a preset temperature of 280° C.to form a molded object (¼ inch thick) for evaluating physicalproperties. The Izod impact strength of the resultant molded object at0° C. and the melt viscosity of the pellets at 280° C. are shown inTable 3 below. The results of visual evaluation of transparency are alsoshown in Table 3, wherein ⊙ represents being highly transparent, ◯represents being ordinarily transparent, Δ represents being slightlyopaque, and x represents being opaque.

EXAMPLES 15 AND 16

Molded objects were formed as in Example 14 except that thecrosslinkable silyl group-containing polymers produced in Examples 2 and3 were used, and evaluations were performed. The results thereof areshown in Table 3.

COMPARATIVE EXAMPLE 3

A molded object was formed as in Example 14 without compounding thecrosslinkable silyl group-containing polymer, and evaluations wereperformed as in Example 14. The results thereof are shown in Table 3.

TABLE 3 Izod Crosslinkable silyl impact Melt group-containing strengthviscosity polymer (kJ/m²) (poise) Transparency Example 14 Example 1 103600 ◯ Example 15 Example 2 12 3400 ◯ Example 16 Example 3 15 3200 ⊚Comparative —  3 5100 ⊚ Example 3

As is evident from Table 3, when the crosslinkable silylgroup-containing polymers of the present invention are used as resinmodifiers, the impact resistance and moldability of the molded objectsare greatly improved, and transparency is not substantially impaired.

EXAMPLE 17

A poly(butylene terephthalate) resin, DURANEX 2002 (manufactured byPolyplastic Co., Ltd.), (80 parts by weight), Topanol CA (manufacturedby Lipre Co., Ltd.) (0.3 parts by weight) as a stabilizer, andAdekasutabu PEP-36 (manufactured by Asahi Denka Co., Ltd.) (0.3 parts byweight) as a HALS were prepared and compounded with 20 parts by weightof the crosslinkable silyl group-containing polymer produced in Example1 and 0.2 parts by weight of dibutyltin diacetylacetonate. Using avent-type twin-screw extruder (32 mm, L/D=25.5), the resultantcomposition was extrusion-kneaded at a preset temperature of 245° C. andpelletized. The resultant pellets were dried at 80° C. for 15 hours, andinjection molding was then performed at a preset temperature of 250° C.to form a molded object (⅛ inch thick) for evaluating physicalproperties. The Izod impact strength at 23° C., the spiral flow, and theresult of visual evaluation of transparency (wherein ⊙ represents beinghighly transparent, ∘ represents being ordinarily transparent, Δrepresents being slightly opaque, and x represents being opaque) of theresultant molded object are shown in Table 4 below.

EXAMPLES 18 AND 19

Molded objects were formed as in Example 17 except that thecrosslinkable silyl group-containing polymer produced in Examples 2 and3 were used, and evaluations were performed. The results thereof areshown in Table 4.

COMPARATIVE EXAMPLE 4

A molded object was formed as in Example 17 without compounding thecrosslinkable silyl group-containing polymer. The Izod impact strengthat 23° C., the spiral flow, and the result of visual evaluation oftransparency of the resultant molded object are shown in Table 4.

TABLE 4 Crosslinkable silyl Izod impact Spiral group-containing strengthflow polymer (kJ/m²) (mm) Transparency Example 17 Example 1 16 220 ◯Example 18 Example 2 15 210 ◯ Example 19 Example 3 19 330 ⊚ Comparative—  3 110 ⊚ Example 4

As is evident from Examples 17 to 19 and Comparative Example 4, when thecrosslinkable silyl group-containing polymers of the present inventionare used as resin modifiers, impact resistance and moldability aregreatly improved, and transparency is not substantially impaired.

INDUSTRIAL APPLICABILITY

In accordance with the production process of the present invention, acrosslinkable silyl group-containing vinyl polymer can be producedeasily, and moreover, purification steps can be simplified, thusminimizing production cost. Furthermore, in addition to solutionpolymerization, a water-based polymerization technique, such as emulsionpolymerization or suspension polymerization, can also be employed.Consequently, in industrial production, improved safety and low cost areensured. A curable composition containing the crosslinkable silylgroup-containing polymer is excellent in oil resistance, heatresistance, weatherability, low staining properties, and compression setcharacteristics, and easy to handle. When the crosslinkable silylgroup-containing polymer is used as a resin modifier, the impactresistance and moldability of the resultant molded object are greatlyimproved, and high transparency is exhibited.

1. A process for producing a crosslinkable silyl group-containingpolymer comprising the steps of: radically polymerizing a radicallypolymerizable vinyl monomer in the presence of at least onethiocarbonylthio group-containing compound selected from the groupconsisting of a compound represented by general formula (1):

(wherein R¹ is a p-valent organic group of 1 or more carbon atoms whichmay contain one of nitrogen, oxygen, sulfur, halogen, silicon,phosphorus, and metal atoms, or which may be a polymer; Z¹ is a hydrogenatom, halogen atom, or monovalent organic group of 1 or more carbonatoms which may contain one of nitrogen, oxygen, sulfur, halogen,silicon, and phosphorus atoms, or which may be a polymer; when pluralZ¹s are present, the plural Z¹s may be the same or different; and p isan integer of 1 or more), and a compound represented by general formula(2):

(wherein R² is a monovalent organic group of 1 or more carbon atomswhich may contain one of nitrogen, oxygen, sulfur, halogen, silicon,phosphorus, and metal atoms, or which may be a polymer; Z² is an oxygenatom (when q=2), sulfur atom (when q=2), nitrogen atom (when q=3), orq-valent organic group of 1 or more carbon atoms which may contain oneof nitrogen, oxygen, sulfur, halogen, silicon, and phosphorus atoms, orwhich may be a polymer; plural R²s may be the same or different; and qis an integer of 2 or more), to prepare a thiocarbonylthiogroup-containing polymer; converting the thiocarbonylthio group of thepolymer into a mercapto group; and coupling the polymer with a compoundhaving a crosslinkable silyl group and an isocyanato group in eachmolecule via the mercapto group.
 2. The process according to claim 1,wherein the thiocarbonylthio group-containing compound is represented bygeneral formula (3):

(wherein R³ is a divalent organic group which may contain one ofnitrogen, oxygen, sulfur, halogen, silicon, phosphorus, and metal atoms,or which may be a polymer; each Z³ is a hydrogen atom, halogen atom, ormonovalent organic group of 1 or more carbon atoms which may contain oneof nitrogen, oxygen, sulfur, halogen, silicon, and phosphorus atoms, orwhich may be a polymer; and Z³s may be the same or different).
 3. Theprocess according to claim 1, wherein the vinyl monomer is at least onecompound selected from the group consisting of styrene, α-methylstyrene,vinyl chloride, vinylidene chloride, methacrylate esters, acrylateesters, methacrylic acid, acrylic acid, methacrylamide, acrylamide,methacrylonitrile, acrylonitrile, vinyl acetate, maleic anhydride, andmaleimide compounds.
 4. The process according to claim 1, wherein thevinyl monomer is at least one compound selected from the groupconsisting of methacrylate esters and acrylate esters.
 5. The processaccording to claim 1, wherein the thiocarbonylthio group of thethiocarbonylthio group-containing polymer is converted into the mercaptogroup by a reaction with a processing agent comprising at least onecompound selected from the group consisting of bases and acids.
 6. Theprocess according to claim 1, wherein the thiocarbonylthio group of thethiocarbonylthio group-containing polymer is converted into the mercaptogroup by a reaction with a processing agent comprising at least onecompound selected from the group consisting of ammonia, hydrazine, andamine compounds.
 7. The process according to claim 6, wherein theprocessing agent is at least one compound selected from the groupconsisting of ammonia, primary amine compounds with a boiling point of100° C. or less, and secondary amine compounds with a boiling point of100° C. or less.
 8. The process according to claim 1, wherein thecompound having a crosslinkable silyl group and an isocyanato group ineach molecule is a compound represented by general formula (4):OCN—(CH₂)_(n)—Si(R⁴)_(3-a)(X)_(a)  (4) (wherein R⁴ is an alkyl group, asubstituted alkyl group, an aryl group, a substituted aryl group, anaralkyl group, a substituted aralkyl group, or a triorganosiloxy group;X is a hydroxyl group or a hydrolyzable group; n is an integer of 3 ormore; a is 1, 2, or 3; when a is 1, two R⁴s may be the same ordifferent; and when a is 2 or 3, two or three Xs may be the same ordifferent).
 9. The process according to claim 8, wherein the compoundhaving a crosslinkable silyl group and an isocyanato group in eachmolecule is at least one compound selected from the group consisting ofγ-isocyanatopropyltrimethoxysilane,γ-isocyanatopropyldimethoxymethylsilane,γ-isocyanatopropyltriethoxysilane, andγ-isocyanatopropyldiethoxymethylsilane.
 10. The process according toclaim 1, wherein the coupling is performed in the presence of a urethaneformation catalyst.
 11. The process according to claim 1, wherein thecoupling is performed in the presence of a tin-based urethane formationcatalyst containing a sulfur atom.
 12. A crosslinkable silylgroup-containing polymer produced by the process according to claim 1.13. A curable composition comprising the crosslinkable silylgroup-containing polymer according to claim
 12. 14. The curablecomposition according to claim 13, further comprising a condensationcatalyst.